The present invention relates to an automatic gas shut off valve and, more particularly, to a propane gas shut off valve for a barbeque grill not allowing the propane to flow if a the grill is unintentionally left on for an extended period of time.
When using a gas grill to barbeque food it is common that the grill is turned on and allowed to heat up prior to placing food on the grill, the food is then placed on the grill, cooked, and removed from the grill. Many times the user of the grill will then decide to leave the burners on so the remnants of the food may be burned off, then leaving the grill and returning to the kitchen where the user is more interested in enjoying the grilled food than remembering to return to the grill and shut the burners off. At this point many things can happen, first of all the grill becomes very hot and may become a fire hazard, second the propane in the tank is wasted by being allowed to run until empty, third it is a hassle the next time the user decides to use the grill, they must remove the tank and make a visit to the propane vendor. The current system leaves room for human error. By using this Gas Grill Propane Monitor valve it would set a time limit on the time a grill would be allowed to run and eliminate the problems mentioned, making grilling a safer activity.
There are other inherent prior art which monitor the last known activity by means of a motion detector of lid sensor installed in the gas line after the pressure reducer valve such as listed in U.S. Pat. No. 5,628,242.
Another prior art approach is a gas valve regulated by a mechanical spring turned to a anticipated amount of time.
These prior art approaches have inherent short comings; By installing the valve after the pressure reducer in the gas line it may require cutting the gas line which may lead to propane leaks and even if there was a threaded connection between the gas hose and the grill many grills today are surrounded by metal enclosures which would make it difficult to access if a device was installed in this area. Since it would be necessary to access each time a grill was used.
Other current inventions call for an egg timer approach which is a manual way of going about shutting off the fuel.
Prior inventions have addressed many of the problems associated with grilling and using gas to cook, but none have been so simple as the Gas Grill Propane Monitor to install on any existing grill; or perform the function of protecting against hazards without the user having to change their habits of using a gas grill. The Gas Grill Propane Monitor is an install it and forget about it device that truly protects against human error.
It is therefore an object of the invention to prevent a possible fire hazard and waste of fuel when a gas grill is inadvertently left on after use by automatically shutting off the fuel supply.
It is another object of the invention to automatically detect when a barbeque grill is activated by means of employing the preferred element on/off switch, thermostat sensor.
It is another object of the invention to begin monitoring time once a barbeque grill is turned on.
It is another object of the invention to adjust the timing device""s limit by means of a potentiometer to set a destination point or time-on make point.
It is another object of the invention to shut the fuel supply off if the timing device is allowed to accrue minutes equal to the preset amount of time set by the potentiometer.
It is another object of the invention to terminate propane supply if the power source of the invention drops below the necessary voltage to power it.
In accordance with the present invention, there is provided, a prior art latching valve installed in between a propane tank and a barbeque grill pressure reducer, once a grill is turned on, a automatically activated on/off switch or more particularly using a preferred element thermostat sensor switch, activates a timing device which begins monitoring the time since the grill was turned on. The timing device, employs a user adjustable potentiometer to set the amount of time the timer will accrue prior to sending power to a latching valve, resulting in terminating gas flow. So if a gas grill is used and is always shut off prior to that time set by the potentiometer no action will result, but if the gas grill is inadvertently left on for a period of time which equals that set by the potentiometer the latching valve would receive power from the timing device and be closed. At this point a reset button on the timing device must be pressed sending a reverse polarity pulse to the latching valve to reopen it. This device is a safety feature that could be ignored once installed, but save the fuel in the tank and avoid possible fire hazards if the grill is forgotten.